I don’t think there is a way to disable the feature, it sounds like a bug in the Nokia. My only suggestion would to be to use the Tasker app and write an automation that automatically turns off Adaptive Brightness if it is turned on. If the brightness changes when Adaptive Brightness first turns on you could have the task restore the previous brightness also. I know this shouldn’t be needed but it is an option.
I don’t think there is a way to disable the feature, it sounds like a bug in the Nokia. My only suggestion would to be to use the Tasker app and write an automation that automatically turns off Adaptive Brightness if it is turned on. If the brightness changes when Adaptive Brightness first turns on you could have the task restore the previous brightness also. I know this shouldn’t be needed but it is an option.